Tissue Ablation and Cautery with Optical Energy Carried in Fluid Stream

ABSTRACT

Methods and systems for modifying tissue use a pressurized fluid stream carrying coherent light energy. The methods and systems may be used for resecting and debulking soft and hard biological tissues. The coherent light is focused within a stream of fluid to deliver energy to the tissue to be treated.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of provisional application No.61/097,497, filed on Sep. 16, 2008, and of provisional application No.61/034,412, filed on Mar. 6, 2008, the full disclosures of which areincorporated herein by reference. The subject matter of this applicationis related to that of commonly-owned application Ser. No. 11/968,445(Attorney Docket No. 026918-000110US) which claimed the benefit ofprovisional application No. 60/883,097 (Attorney Docket No.026918-000100US), filed on Jan. 2, 2007, the full disclosures of whichare incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to medical methods and devices.In particular, the present invention relates to methods and devices forapplying energy to ablate, cut, drill, or otherwise modify soft or hardtissues.

Both water jet technology and laser technology have been proposed forvarious tissue cutting and modification protocols. While each of theseapproaches has achieved commercial success, neither is ideally suitedfor all tissue modification protocols. For example, water jet or streamcutting alone does not cauterize tissue and therefore cannot preventexcessive bleeding. Furthermore, it can require very high pressure waterdelivery systems which can be difficult to control. Similarly, the useof lasers for modifying tissue can require very high energies, which canonly be generated with large high power and expensive laser equipment.While laser technology can be effectively applied to cauterize tissueand stop bleeding, an extensive tissue zone of thermal damage isunavoidable. The consequences are the formation of edema and swelling ofthe treated tissue. With prostate tissue for example, tissue edema andswelling may result with the patient going into urinary retentionrequiring catheterization. Thus, improved energy-based methods anddevices for ablating, cutting, drilling, and otherwise modifyingtissues, would be desirable.

A number of medical conditions affect the male urethra causing a varietyof symptoms including painful or difficult urination, a swollenprostate, blood in the urine, lower back pain, and the like. Some ofthese conditions, such as prostatitis, are bacterial infections whichcan be treated with antibiotics and other drugs. Other conditions,however, such as benign prostatic hyperplasia (BPH) and prostaticcarcinoma, result in enlargement of the prostate and obstruction of theurethra, sometimes leading to complete loss of bladder function.

Both BPH and prostatic cancer require treatments which remove, resect,or shrink tissue in the prostate surrounding the urethra. Commontreatments include transurethral resection of the prostate (TURP) wherea resectoscope is placed in the urethra and used to remove excessprostatic tissue. Another procedure, referred to as transurethralincision of the prostate (TUIP), relies on cutting muscle adjacent tothe prostate to relax the bladder opening to relieve difficulty inurination. More recently, a procedure referred to as transurethralneedle ablation (TUNA) has been introduced where a needle is advancedthrough the urethra into the prostate and used to deliver energy, suchas microwave, radiofrequency, or ultrasound energy, to shrink the sizeof the prostate, again relieving pressure on the urethra. Laserresection or ablation using transurethral optical fibers also finds use.

One minimally invasive laser resection protocol is photoselectivevaporization of the prostate (PVP) where a laser beam with output powersranging from 60 to 120 W is directed from the urethra against prostatictissue to achieve irradiance (power density) levels over a certainvolumetric power density, referred to as a vaporization threshold, belowwhich tissue coagulation rather than vaporization occurs. As theirradiance level increases above the vaporization threshold, tissuevaporization increases and coagulation decreases. Lasers, even thosehaving the highest possible beam quality, produce divergent beams.Therefore, the laser spot size enlarges with increasing probe distancefrom the tissue, and the power density decreases. reducing the rate ofvaporization. Hence, in order to maximize the rate of tissuevaporization and thereby limit the extent of the zone of thermal damagecharacterized by tissue coagulation left after the procedure, thephysician must steadily hold the fiber a fixed distance (e.g., 1-2 mm)away from the tissue and slowly scan the beam over the target tissuewithout varying the distance. Clearly, the effectiveness and duration ofthis procedure is highly dependent on the skill of the treatingphysician and the use of a high-power laser.

While generally successful, none of these methods are adequate to treatall patients and all conditions. In particular, patients having severetissue intrusion into the urethral lumen resulting from BPH or prostaticcancer are difficult to treat with minimally invasive protocols whichrely on tissue shrinkage rather than resection. Additionally, thosetreatments which resect tissue often cause substantial bleeding whichcan be difficult to staunch. Thus, many of these patients willeventually require conventional surgical resection or follow-upprocedures to stop bleeding.

For these reasons, it would be desirable to provide alternative andimproved tissue-modifying systems which rely on the application ofenergy from one or more sources to the tissue. In particular, it wouldbe desirable to provide minimally invasive methods and devices whichprovide for enlarging the luminal area and/or volumetric resection oftissue surrounding the urethra. It would be particularly desirable ifsuch methods and devices were transurethrally introduced and providedfor rapid removal or destruction of such tissues surrounding the urethrawhere the removal or destruction products can be removed from the lumento relieve pressure on the urethra, even where large volumes of tissueare being removed. It would be particularly desirable if the methods anddevices allowed for controllable tissue resection and/or ablation depthfrom very shallow depths to several millimeters or deeper. It would alsobe advantageous if the ablation could simultaneously cauterize treatedtissue to limit bleeding. It would also be desirable if the depth ofresidual coagulated tissue that remains after tissue ablation wereminimized or completely eliminated. It would be a further advantage ifthe use of a high-power laser were not required. It would beparticularly beneficial if the methods and devices allowed for rapid andcontrolling tissue ablation or resection which is less dependent onskill of the treating physician. Methods and devices for performing suchprotocols should present minimal risk to the patient, should berelatively easy to perform by the treating physician, and should allowfor alleviation of symptoms with minimal complications and side effectseven in patients with severe disease. At least some of these objectiveswill be met by the inventions described below.

2. Description of the Background Art

The use of water or other fluid jets as waveguides for carrying a laserbeam for cutting and other manufacturing operations is described in U.S.Patent Application No. 2007/0278195, published Canadian application2,330436 A1, PCT publication WO 99/56907, and U.S. Pat. Nos. 7,163,875;5,902,499; and 5,773,791. U.S. Patent Application No. 2007/0025874describes the use of laser fluid jets for disinfecting hands. The use oflasers for cutting biological tissue is described in U.S. PatentApplication No. 2002/0128637 and for ablating prostate tissue isdescribed in U.S. Pat. Nos. 5,257,991; 5,514,669; and 6,986,764. Use ofa transurethral endoscope for bipolar radiofrequency prostatevaporization is described in Boffo et al. (2001) J. Endourol.15:313-316. Pressurized water streams for effecting surgical incisionsare described in U.S. Pat. Nos. 7,122,017 and 5,620,414, and fordrilling teeth are described in U.S. Pat. No. 7,326,054. U.S. Pat. Nos.5,785,521 and 6,607,524 describe the use of laser energy to causethermo-elastic failure and fracture of hard biological materialscombined with water/air technology to cool and remove (or furtherfracture) the already fractured material and debris from the treatmentsite. Radiofrequency discharge in saline solutions to producetissue-ablative plasmas is discussed in Woloszko et al. (2002) IEEETrans. Plasma Sci. 30:1376-1383 and Stalder et al. (2001) Appl. Phys.Lett. 79:4503-4505. Air/water jets for resecting tissue are described inJian and Jiajun (2001) Trans. ASME 246-248. US2005/0288639 described aneedle injector on a catheter based system which can be anchored in aurethra by a balloon in the bladder. U.S. Pat. Nos. 6,890,332;6,821,275; and 6,413,256 each describe catheters for producing an RFplasma for tissue ablation. Other patents and published applications ofinterest include: U.S. Pat. Nos. 7,015,253; 6,953,461; 6,890,332;6,821,275; 6,451,017; 6,413,256; 6,378,525; 6,296,639; 6,231,591;6,217,860; 6,200,573; 6,179,831; 6,142,991; 6,022,860; 5,994,362;5,872,150; 5,861,002; 5,817,649; 5,770,603; 5,753,641; 5,672,171;5,630,794; 5,562,703; 5,322,503; 5,116,615; 4,760,071; 4,636,505;4,461,283; 4,386,080; 4,377,584; 4,239,776; 4,220,735; 4,097,578;3,875,229; 3,847,988; US2002/0040220; US2001/0048942; WO 93/15664; andWO 92/10142.

BRIEF SUMMARY OF THE INVENTION

Methods, devices, and systems according to the present invention providefor delivery of coherent light and fluid energy to ablate, resect,drill, cut, or otherwise modify tissue. The tissues to be treated can besoft tissue, such as muscle, organ tissue, nerve tissue, cerebraltissue, skin tissue, glandular tissue or the like, or can be hardtissue, such as tooth, bone, cartilage, or the like. Particulartreatments include ablation, such volumetric tissue ablation wherevolumes or regions of the tissue are vaporized, shrunk, necrosed or thelike. The tissue modification can also be cutting where the tissue issevered into pieces or regions along a resection plane, or can bedrilling where a hole is formed into the tissue, such as drilling into atooth, or the like.

The present invention is particularly intended for treating/modifyingsoft and hard biological tissue. Depending on the power levels,treatment times, and treatment patterns selected, the present inventioncan provide for tissue resection, e.g. cutting along a line of tissue;tissue volume reduction; tissue surface modification; and the like. Aparticular advantage of the present invention arises from thesimultaneous delivery of both fluid energy (constant or pulsating) inthe form of a pressurized liquid medium and coherent light energy whichwill be propagated with constant power density through the fluid mediumby total internal reflection thereby eliminating the need of laserfocus-distance control. Where the pressurized fluid medium isprincipally relied on for cutting or tissue ablation, the coherent lightcan be delivered at an energy level selected to provide cauterization,i.e. the staunching of bleeding which would otherwise occur as a resultof the tissue resection or ablation. Alternatively, by using highercoherent light energy levels, the coherent light can work together withthe pressurized fluid stream to achieve faster, deeper, or otherwiseenhanced cutting, tissue volume reduction, or other tissue modificationswith significantly diminished laser power requirements as compared tocurrent treatments such as photoselective vaporization of the prostate(PVP).

Specific prostate treatments according to the present invention comprisepositioning a coherent light and fluid energy source within the urethraand directing a fluid stream carrying the energy radially outwardly fromthe energy source toward the urethral wall within the prostate. Thefluid stream will usually be moved relative to the urethra to remove apre-defined volume of prostate tissue surrounding the urethral lumen inorder to partially or fully relieve the compression and/or obstruction.In other embodiments, the treatments of the present invention may becombined with chemotherapy and other forms of drug delivery, as well astreatment with external X-ray and other radiation sources andadministration of radiopharmaceuticals comprising therapeuticradioisotopes. For example, one or more drugs may be combined with thesaline or other fluid which is being delivered. The combinationliquid/coherent light delivery can be used to both resect tissue andwash the tissue away while leaving intra-prostatic blood vessels,capsule, and sphincter muscle undamaged.

Benefits of the high pressure liquid/light energy source include reducedor no bleeding with reduced or no need for cauterization and decreasedrisk of perforating or otherwise damaging the capsule of sphinctermuscles. Alternatively, the device which is used to position thefluid/light energy source can be utilized to separately deliver adesired chemotherapeutic or other drug (as just set forth), eitherbefore, during, or after energy treatment according to the presentinvention. While the present invention is specifically directed attransurethral treatment of the prostate, certain aspects of theinvention may also find use in the treatment of other body lumens,organs, passages, tissues, and the like, such as the ureter, colon,esophagus, lung passages, bone marrow, and blood vessels.

Thus, in a first aspect of the present invention, methods for modifyingtissue comprise generating a stream of a light transmissive fluidmedium, such as saline, water, alcohol, liquefied CO₂ and otherliquefied gases (gases which are liquids at the pressure and temperatureof use), fluid containing drug compounds such as vasocontricting agents(to reduce bleeding) and/or anesthetic agents (to reduce pain) and/oranti-inflammatory agents, antibiotics (to reduce infection), or thelike. A source of coherent light, such as a laser, is coupled to thelight transmissive medium through a waveguide or other optical couplerso that light is transmitted through said stream by total internalreflection. The fluid stream which carries the coherent light is thendirected at target tissue, such as within the prostate.

While a particular advantage of the present invention is thesimultaneous delivery of a pressurized fluid stream and laser or otheroptical energy, in some instances either the fluid stream or the opticalenergy may be delivered alone. For example, it may be desirable todeliver the fluid stream without optical energy to perform conventionalwater jet resection or volume reduction of tissue. After such water jettreatment, the optical energy can be added to cauterize and/or perform aprocedure at a higher total energy. Optionally, the pressure, volume,flow velocity, temperature, or other characteristics of the fluid streammay be varied depending on whether optical energy is present, e.g.,cauterization may be performed at lower pressures than tissue resection.In all cases the removed tissue and/or remaining tissue can be used forhistological evaluation or other diagnostic procedures. It is aparticular advantage that the removed tissue has not been vaporized orotherwise damaged to the extent it is with PVP and the subsequentanalysis is impaired.

The liquid stream may be generated in a variety of ways, typically beingdelivered under pressure through a nozzle, where the nozzle typicallyhas an area in the range from 0.0005 mm² to 5 mm², usually from 0.02 mm²to 0.2 mm², and the pressure is in the range from 10 psi to 1000 psi,typically from 50 Psi to 500 Psi. The light which is coupled into thelight transmissive fluid will typically have a power level in the rangefrom 10 mW to 40 W, typically from 100 mW to 10 W. Suitable lasersources include solid state lasers. For treating prostate tissue, thestream will be directed radially outward from a location in the urethrawithin the prostate.

Typically, prostate treatment will comprise positioning a probe withinthe urethra, directing the pressurized stream of light transmissiveliquid medium radially outward from the probe to the prostate tissuesurrounding the urethra. The coherent light is focused within the streamof liquid medium as the stream is directed at the prostate tissue. Inthis way, tissue volume reduction of the prostate may be efficientlycarried out, while the coherent light can provide cauterization withminimal laser power to reduce the bleeding associated with thetreatment.

In a second aspect of the present invention, a system for deliveringlaser or other coherent light energy to tissue comprises a tissue probe,a fluid nozzle on the probe, and a waveguide disposed within the probe.The tissue probe is suitable for introducing into solid tissue, tissuelumens, body cavities, or the like. In the exemplary embodiment, thetissue probe is suitable for transurethral introduction into theprostate so that a distal end of the probe is positioned within theprostate. A nozzle is provided for emitting a stream of lighttransmissive fluid, and a waveguide transmits coherent light into thefluid so that the fluid acts as a guide for further directing thecoherent light to the tissue for treatment. Usually, the tissue probewill be adapted to be advanced through the urethra, but a wide varietyof other specific designs would also be available for delivery intosolid tissue, body lumens, or body cavities. Probes of the presentinvention typically have at least one central axial passage fordelivering the light transmissive fluid to the nozzle, and the nozzle istypically disposed on the probe to deliver the fluid radially outwardly(laterally) under pressure.

In an exemplary embodiment, the probe comprises an outer tube having anaxial lumen and an inner fluid delivery tube reciprocally mounted in theaxial lumen. A central axial passage is disposed in the inner fluiddelivery tube, and the waveguide is disposed in the central axialpassage. In this way, the light transmissive fluid can be deliveredthrough the central axial passage and diverted outwardly through thenozzle. The waveguide would be disposed to deliver coherent lightthrough the central axial passage and to reflect or otherwise divert thelight radially so that it is focused within the light transmissive fluidbeing delivered through the nozzle. By focusing the energy as it isemanating from the tissue probe, the light will be delivered through thefluid stream to assist in propagation.

In the specific embodiments, the distal end of the inner fluid deliverytube is disposed adjacent to a window in the outer tube. The inner tubemay then be reciprocated and/or rotated relative to the outer tube sothat the fluid stream and coherent light emanating from the inner fluiddelivery tube may be delivered into tissue adjacent to or surroundingthe outer tube through the window.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a device suitable for performingintraurethral prostatic tissue debulking in accordance with theprinciples of the present invention.

FIG. 2 is a detailed illustration of the pressurized fluid/coherentlight delivery mechanism used in the device of FIG. 1.

FIGS. 2A and 2B illustrate two alternative arrangements for focusingcoherent light from a waveguide into a pressurized liquid stream in themechanism of FIG. 2.

FIGS. 3A-3C illustrate use of the device of FIG. 1 in performingprostatic tissue debulking.

FIGS. 4A-4E illustrate an alternative design for the tissue debulkingdevice of the present invention, illustrating specific components andfeatures for delivering fluids, inflating balloons, rotating andreciprocating the fluid and light delivery mechanism, and the like.

FIG. 5 is a detailed, cross-sectional view of a portion of the rotatingand reciprocating fluid and light delivery mechanism of FIGS. 4A-4E.

FIG. 6 illustrates use of the device of FIGS. 4A-4E in debulking tissue.

FIG. 7 is a schematic illustration of a device constructed in accordancewith the present invention suitable for performing tissue cutting orother procedures where an axial pressurized liquid stream is deliveredfrom a distal tip of the device and carries focused coherent light froma waveguide.

FIG. 8 illustrates another handheld device constructed in accordancewith the principles of the present invention, where the pressurizedliquid stream carrying the coherent light is directed laterally from theshaft of the device.

FIG. 9 illustrates a robotically deployed pressurized fluid/coherentlight delivery mechanism.

FIG. 10 illustrates use of the device of FIG. 7 as a scalpel for cuttingtissue.

FIG. 11 illustrates the use of the device of FIG. 8 for drilling atooth.

FIG. 12 illustrates a system for deploying a tissue debulking devicesimilar to that illustrated in FIGS. 4A-4E and including a tissuestabilization sheath and schematically illustrating the various drivemechanisms in accordance with the principles of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, an exemplary prostatic tissue debulking device 10constructed in accordance with the principles of the present inventioncomprises a catheter assembly generally including a shaft 12 having adistal end 14 and a proximal end 16. The shaft 12 will typically be apolymeric extrusion including one, two, three, four, or more axiallumens extending from a hub 18 at the proximal end 16 to locations nearthe distal end 14. The shaft 12 will generally have a length in therange from 15 cm to 25 cm and a diameter in the range from 1 mm to 10mm, usually from 4 mm to 8 mm. The shaft will have sufficient columnstrength so that it may be introduced upwardly through the male urethra,as described in more detail below.

The shaft will include a fluid/coherent light energy source 20positioned near the distal end 14 of the shaft 12. The source 20, inturn, is connected to an external light source 22 and light transmissivefluid source 28. Distal to the energy source 20, an inflatable anchoringballoon 24 will be positioned at or very close to the distal end 14 ofthe shaft. The balloon will be connected through one of the axial lumensto a balloon inflation source 26 connected through the hub 18. Inaddition to the light source 22, fluid pump 28, and balloon inflationsource 26, the hub will optionally further include connections for anaspiration (a vacuum) source 30, and/or an insufflation (pressurized CO₂or other gas) source 32. In the exemplary embodiment, the fluid pump 28can be connected through an axial lumen (not shown) to one or moreport(s) 34 on an inner fluid delivery tube 35. The aspiration source 30can be connected to a window or opening 38, usually positionedproximally of the energy source 20, while the insufflation source 32 canbe connected to a port 36 formed in the wall of shaft 12. The energywill be directed through the window 38 as described in more detailbelow.

Referring now to FIG. 2, the fluid/coherent light energy source 20 isdefined by window 38 in the wall of shaft 12. The inner fluid deliverytube 35 is reciprocatably and rotatably mounted within a central lumenof the shaft 12 so that the port 34 may be rotated and/or axiallyadvanced and retracted within the window relative to the shaft. Theinner fluid delivery tube 35 has a central passage 40 which isattachable to the transmissive fluid pump 28 through the hub 18 to carrythe transmissive fluid under pressure and emit a fluid or jet streamthrough the port 34 in a lateral direction. An optical waveguide 42 isalso positioned within the central passage 40 of the inner fluiddelivery tube 35.

As shown in FIGS. 2A and 2B, the light transmissive fiber 42 includes anelement 44 (FIG. 2A) or 46 (FIG. 2B) for transversely or laterallyreflecting light transmitted through the fiber so that it may be emittedthrough the port 34 and into the flowing fluid stream passingtherethrough. It will be desirable that the light emitted from theoptical waveguide 42 be focused at a point F within the flowing fluidstream so that the light may then be transmitted and propagated throughthe stream by total internal reflection. Reflective element 44 may havea parabolic or other shaped surface to effect the desired focusing. Incontrast, the reflective element 46 may have a flat, non-focusingsurface that passes the light through a focusing lens 48, as shown inFIG. 2B.

Referring now to FIGS. 3A-3C, the prostatic tissue debulking device 10is introduced through the male urethra U to a region within the prostateP which is located immediately distal to the bladder B. The anatomy isshown in FIG. 3A. Once the catheter 10 has been positioned so that theanchoring balloon 24 is located just distal of the bladder neck BN (FIG.3B) the balloon can be inflated, preferably to occupy substantially theentire interior of the bladder, as shown in FIG. 3C. Once the anchoringballoon 24 is inflated, the position of the prostatic tissue debulkingdevice 10 will be fixed and stabilized within the urethra U so that theenergy source 20 is positioned within the prostate P. It will beappreciated that proper positioning of the energy source 20 depends onlyon the inflation of the anchoring balloon 24 within the bladder. As theprostate is located immediately proximal to the bladder neck BN, byspacing the distal end of the energy delivery region very close to theproximal end of the balloon, the delivery region can be properlylocated, typically being spaced by a distance in the range from 0 mm to5 mm, preferably from 1 mm to 3 mm from the bladder neck. After theanchoring balloon 24 has been inflated, light and high fluid energy canbe delivered into the prostate for debulking as shown by the arrows inFIG. 2, while simultaneously removing the debulked/destroyed tissue andresidual fluid by aspiration, typically at both ends of the window, asshown by the arrows 49 in FIG. 3C. Alternatively, the prostate (urethra)can be insufflated or flushed at a pressure greater than that of theaspiration (exhaust) system to enhance tissue and debris collection.Once the energy has been delivered for a time and over a desired surfaceregion, the energy region can be stopped.

As shown in FIG. 3C, the inner fluid delivery tube 35 may be axiallytranslated and/or rotated in order to sweep the fluid/coherent lightstream 47 over the interior of the urethra within the prostate P. Theenergy carried by the fluid/light stream both ablates the prostatictissue and cauterizes the tissue to limit bleeding after debulking. Oncea sufficient volume of tissue has been removed, the fluid stream andlight source may be turned off, the balloon 24 deflated, the catheter 10removed from the urethra.

Referring now to FIGS. 4A-4E, a device 60 constructed in accordance withthe principles of the present invention comprises a central shaft 62having a window 64 near a distal end thereof. A hypotube 66 is carriedin a proximal bushing 68 (FIG. 4A) and a threaded region 70 of thehypotube 66 is received within internal threads of the bushing 68. Thus,rotation of the hypotube can axially advance and retract the hypotuberelative to the bushing and central shaft 62. Typically, rotation andaxial movement of the hypotube 66 relative to the bushing 68 and centralshaft 62 is achieved by separately controlling the axial and rotationalmovement of the hypotube, thereby obviating the need for internalthreads and allowing for more versatility of movement within the window64.

The hypotube 66 carries a laser fiber 72 and includes a lumen 74 whichcan receive and deliver a water or other fluid jet as will be describedin more detail below. The central shaft 62 further includes a ballooninflation lumen 76 and lumen 78 for the suction removal of ablatedtissue.

When introduced through the urethra, the device 60 will typically becovered by a sheath 80 as illustrated in FIG. 4D (only a portion of thesheath 80 is shown in FIG. 4A). When fully covered with sheath 80, thewindow 66 is protected so that it reduces scraping and injury to theurethra as the device is advanced.

Once in place, the sheath 80 will be retracted, exposing the window, asillustrated in FIG. 4E. The hypotube 66 may then be rotated and advancedand/or retracted so that the fluid stream FS which carries the opticalenergy may be delivered through the delivery port 82. Additionally, aballoon 84 may be inflated in order to anchor the device 60 within thebladder as previously described.

The fiberoptic wave guide 72 is positioned within a lumen 86 of thehypotube 66, as best seen in FIG. 5. Fluid may be delivered through thelumen, surrounding the laser fiber 72 and ejected through the deliveryport 82 in a lateral direction. Optical energy delivered through fiber72 is also reflected laterally and focused by optional lens 88 so thatthe light is carried by the fluid with internal reflection, as describedpreviously. In use, the hypotube 66 is axially translated within thewindow 64, as shown in FIG. 6. A fluid stream FS which carries theoptical energy is thus directed radially outwardly and against a wall ofthe body lumen, for example of the urethra U. The energized fluid streamFS is able to ablate a desired depth of tissue T, where the depth can becontrolled by the amount of energy delivered and the dwell time or scantime of the fluid stream FS against the tissue.

As shown in FIG. 7, a handheld device 100 may comprise a shaft 102having a distal end with a nozzle 104 oriented to deliver a pressurizedfluid in an axial stream or water jet FS. A laser fiber 106 is disposedaxially within the shaft 102 and terminates in a lens 108 which focuseslight into the axial water jet FS. Water or other fluid is deliveredunder pressure in an annular region 110 of the shaft 102 which surroundsthe laser fiber 106 and is enclosed by an outer perimeter of the shaft.The handheld device 100 is capable of delivering an axial water jet orother pressurized fluid stream and is useful for the manual cutting oftissue or bone, as shown in FIG. 10. The handheld device 100 isconnected to a pressurized fluid source 120, a light source 122, andcontrol circuitry 124, typically by a connecting cord 126. The user canthus control the fluid pressure, the amount of light energy beingintroduced into the fluid stream, movement of the nozzle (velocity,direction, limits, etc.) and other aspects of the treatment protocol inaddition to the axial and rotational movement parameters using thecontrol circuitry. Optionally, although not illustrated, the nozzle 104will be adjustable in order to adjust the width and focus of the fluidstream FS in order to allow further flexibility for the treatment. Whenused for cutting tissue, it can be manipulated much as a scalpel.

FIG. 8 illustrates another handheld device 140 where a principledifference with the device of FIG. 7 is that the water jet or otherpressurized fluid stream FS is directed in a lateral direction fromshaft 142, illustrated as a right angle relative to an axis of the shaft142. Light is delivered through a laser fiber 144 and reflected,typically by an air mirror 146, or side firing optical fiber, laterallynear a distal end 148 of the shaft 142 so that light enters the lateralwater jet or other pressurized fluid stream FS, as described previously.The pressurized fluid stream FS is created through a fixed or adjustablenozzle 150 on the side of the shaft 142, where the fluid is deliveredunder pressure through a lumen or other conduit 152 formed within theshaft 142. As with previous embodiments, a focusing lens 154 isoptionally provided to deliver the coherent light from the laser fiber144 into the water jet or other pressurized fluid stream FS. The deviceof FIG. 8 may be used for a variety of procedures, such as toothdrilling as illustrated in FIG. 11. The lateral flow handheld device 140can be held and manipulated by the dentist in a manner similar toconventional dental drills. The distal end 148 of the shaft will be heldin the mouth so that the stream FS is directed against the dentalsurface to be treated. The shaft 142, laser fiber 144, and flow lumen152 will be connected to a water or other fluid source 160, a suitablelaser light source 162, and control circuitry 164 by connecting cable166.

As illustrated in FIG. 9, a scalpel-type device 180 may be attached to aprogrammable machine arm 182 so that the systems can be used in roboticor other automatic, programmable systems. The programmable machine arm182 may be suspended over tissue T to be treated, and the water jet orother pressurized fluid stream FS carrying the coherent light is used tocut or incise the tissue, as illustrated. The programmable machine armmay be moved in any of the X, Y, and/or Z directions, where the controlis provided by computer or by a manual control system, for example,guided by a joystick or other manipulator.

A system 200 for the automatic deployment of the light fluid deliverydevice 60 of FIGS. 4A-4E is illustrated in FIG. 12. The central shaft62, hypotube 66, and sheath 80 of the device are connected to a controlshaft 202 which in turn is connected to a base unit 204 which includesmotors and control circuitry (not shown) for controlling the relativemovements of the shaft, hypotube, and sheath. The base unit 204 in turnwill be connected to a pressurized fluid source 210, a laser or otheroptical energy source 212, and an external console or controller 214which provides an interface for programming and/or manipulating thedevice 60. In addition to the device 60, the system 200 may include anexternal anchor frame 230 which can be automatically (or manually)advanced and retracted coaxially over the device 60. The anchor frame230 typically includes an atraumatic ring 232 for engaging and anchoringthe system against tissue after the device has been introduced and theballoon expanded to allow the device to be tensioned.

The apparatus and systems of the present invention may include a numberof other optional features. For example, blades or other cuttingelements could be included within the waste lumen(s) 78 of the device 60in order to macerate tissue and other debris as it is beingaspirated/evacuated and removed. The device 60 or any of the otherconfigurations of the present invention may optionally be provided withimaging and illumination fibers, cameras, or the like, in order toprovide for visual monitoring during the procedure. Optical fibers orcameras may be placed anywhere on the device, optionally within thetreatment windows as described before. Means may be provided for keepingthe cameras, fibers, lenses, or the like, clean so that good images maybe obtained. In all of the above embodiments, instead of employingmirrors, the light may be directed into the fluid stream by bending thelight fiber. Additionally, depending on the size of the light fiber andproximity of the fluid nozzle, a focusing lens may or may not benecessary.

While the above is a complete description of the preferred embodimentsof the invention, various alternatives, modifications, and equivalentsmay be used. Therefore, the above description should not be taken aslimiting the scope of the invention which is defined by the appendedclaims.

What is claimed is:
 1. A method for modifying tissue, said methodcomprising: generating a stream of a light transmissive liquid medium;coupling a source of coherent light into the light transmissive mediumso that said light is transmitted through said stream by total internalreflection; and directing the stream to tissue.
 2. A method as in claim1, wherein the liquid stream is generated by passing the liquid mediumunder pressure through a nozzle with a diameter in the range from 0.01mm to 1 mm.
 3. A method as in claim 2, wherein the pressure is in therange from 1 psi to 1000 psi.
 4. A method as in claim 3, wherein thecoherent light has a power level in the range from 10 mW to 40 W.
 5. Amethod as in claim 1, wherein the tissue is luminar tissue and thestream is directed radially outward from the lumen.
 6. A method as inclaim 5, further comprising positioning a probe within the lumen,directing a pressurized stream of the light transmissive liquid mediumradially outwardly from the probe, and focusing the coherent lightwithin the stream of liquid medium as the stream is directed at thetissue.
 7. A method as in claim 6, wherein the nozzle has a diameter inthe range from 0.01 to 1 mm, the pressure is in the range from 1 psi to1000 psi, and the coherent light has a power from 10 mW to 40 W.
 8. Amethod as in claim 1, wherein the tissue is soft tissue and the streamis directed at a line to cut the tissue.
 9. A method as in claim 8,wherein the nozzle has a diameter in the range from 0.01 to 1 mm, thepressure is in the range from 1 psi to 1000 psi, and the coherent lighthas a power from 10 mW to 40 W.
 10. A method as in claim 1, wherein thetissue comprises a tooth or bone and the stream is directed to drillinto the tooth or cut through bone and cartilage.
 11. A method as inclaim 10, wherein the nozzle has an area in the range from 0.01 to 1 mm,the pressure is in the range from 1 psi to 1000 psi, and the coherentlight has a power from 10 mW to 40 W.
 12. A system for delivering laserenergy to tissue, said system comprising: a probe; a nozzle for emittinga stream of a light transmissive fluid; a waveguide for transmittingcoherent light; and wherein the waveguide and nozzle are arranged sothat coherent light from the waveguide is focused in and transmittedthrough the stream of light transmissive fluid by total internalreflection.
 13. A system as in claim 12, further comprising a pump fordelivering the light transmissive fluid to the nozzle at a pressure from1 psi to 1000 psi.
 14. A system as in claim 13, wherein the nozzle has adiameter in the range from 0.01 mm to 1 mm.
 15. A system as in claim 12,further comprising a laser source for delivering coherent light to thewaveguide at a power level in the range from 10 mW to 40 W.
 16. A systemas in claim 12, wherein the probe is adapted to be advanced through theluminal surfaces or lumens.
 17. A system as in claim 13, wherein theprobe has at least one central axial passage for delivering the lighttransmissive fluid to the nozzle.
 18. A system as in claim 14, whereinthe probe comprises an outer tube having an axial lumen and an innerfluid delivery tube reciprocably mounted in the axial lumen, wherein thecentral axial passage is disposed in the inner fluid delivery tube andthe waveguide is disposed in the central axial passage.
 19. A system asin claim 15, wherein the nozzle is disposed to emit the stream of lighttransmissive fluid laterally through a window in the outer tube.
 20. Asystem as in claim 16, wherein the nozzle emits the stream of lighttransmissive fluid at a pressure in the range from 1 psi to 1000 psi andat a stream diameter from 0.01 mm to 1 mm and wherein the coherent lightis transmitted at a power level in the range from 10 mW to 40 W.
 21. Asystem as in claim 12, wherein the probe is hand held and adapted todeliver energy to cut soft tissue.
 22. A system as in claim 21, whereinthe probe comprises a shaft having an axis.
 23. A system as in claim 22,wherein the nozzle is oriented to deliver the stream in an axialdirection relative to the shaft.
 24. A system as in claim 22, whereinthe nozzle is oriented to deliver the stream in a lateral directionrelative to the shaft.
 25. A system as in claim 21, wherein the nozzleemits the stream of light transmissive fluid at a pressure in the rangefrom 1 psi to 1000 psi and at a stream diameter from 0.01 mm to 1 mm andwherein the coherent light is transmitted at a power level in the rangefrom 10 mW to 40 W.
 26. A system as in claim 12, wherein the probe ishand held and adapted to deliver energy to drill teeth or cut throughbone and cartilage.
 27. A system as in claim 26, wherein the probecomprises a shaft having an axis.
 28. A system as in claim 27, whereinthe nozzle is oriented to deliver the stream in a lateral directionrelative to the shaft.
 29. A system as in claim 26, wherein the nozzleemits the stream of light transmissive fluid at a pressure in the rangefrom 1 psi to 1000 psi and at a stream diameter from 0.01 mm to 1 mm andwherein the coherent light is transmitted at a power level in the rangefrom 10 mW to 40 W.
 30. A system as in claim 12, further comprising ananchor frame disposed coaxially over the probe and having a distal endadapted to engage a tissue surface when the probe is introduced into abody lumen.